Figure 2.

Characterizations of photocrosslinkable bioinks and interfacial bonding. A) Schematic of the alternant CVFIT structure constructed by photoinitiated polymerization reaction based on GCC and HPD hydrogels and amidation reaction for interfacial bonding. B) Photographs of sol‐to‐gel transition upon light irradiation (365 nm, 20 mW cm⁻²) within 10 s for i–iii) GCC and iv–vi) HPD formulations. C) ¹H NMR spectra of photoinitiated polymerization reaction upon light irradiation of GCC and HPD formulations. Blue arrows represent proton peak of proteoglycan; red arrows represent proton peak of protein. D) Time‐sweep rheological analyses of GCC and HPD formulations showing the rapid gelation at approximately 5 s. E) Shear and F) compressive moduli of photocrosslinkable hydrogels with different compositions. (ns: no significance). G) Images of hydrogel interfacial force measurement experiments under i,ii) static and iii,iv) dynamic forces. Integrated hydrogels were not detached under force loading. HPD hydrogels were stained by rhodamine (red). Interfacial characterizations showing H) fluorescence staining and I) AFM (atomic force microscopy) images between GCC (fluorescein‐stained, green) and HPD (rhodamine‐stained, red) hydrogels. TR: GCC‐HPD transitional region. J) XPS (X‐ray photoelectron spectroscopy) analyses of the interfacial bonding with 8‐PEG‐NHS treatment on GelMA gel surface. K) The interfacial strength of uniaxial tensile and horizontal shear of the interfacial bonding between GCC and HPD hydrogels. L) The finite element analyses of longitudinal tensile and lateral bending. The tested samples were obtained from the regenerated alternant structural trachea (RT) and the unitary cartilage tube (CT). G: 10% w/v GelMA gel; GC: 10% w/v GelMA/2% w/v CSMA gel; GCC: 10% w/v GelMA/2% w/v CSMA/1% w/v ACMMA gel; H: 2% w/v HAMA gel; HP: 2% w/v HAMA/5% w/v 8‐PEG‐NHS gel; HPD: 2% w/v HAMA/5% w/v 8‐PEG‐NHS/1% w/v ADMMA gel. CHs: chondrocytes; FBs: fibroblasts.